Vapor canister or vented gas cap

[Cuda U Code]

After researching this topic, I am still confused so I hope someone can answer this question. I have a 70 Cuda 440, 4 barrel carb, and 4 speed manual trans.
car was built in April 1970.
The question is: would this car have been built with a Vapor canister and return line to the tank, or did it have a vented gas tank cap, or neither? At present, it doesn’t have either and I am experiencing 2 issues that point towards a problem with vacuum in the tank. The first problem is a grumbling noise coming from the tank after the car has been warmed up and then turned off, the second indicator is if the car sits for a week or longer, it takes several seconds of cranking it over before getting fuel to the carburetor. Any help is greatly appreciated.

 

[1972 AAR Cuda]

I understood the gas tank vent system (charcoal canister) was a California only requirement in 72. My 72 340 Cuda (California car) was built with the charcoal canister. Maybe others can add more info (or correct me if I am wrong).

 

[Chryco Psycho]

In 70 all had vented caps which changed in 71, the only exception in 70 might be N95 california emissions cars

 

[Xcudame]

Chryco Physco is spot on! My 70 Challenger WSS built in LA has the 1/4" fuel return line and the extra vent tube in the truck. Federal cars had the vented cap in 1970.

 

[Steve340]

I purchased a repro vented/pressure cap for my 1971 on Ebay for around $40. That was a year or two ago so they have likely got more expensive.

 

[MoparCarGuy]

The 1970 VENTED ANTI SURGE fuel cap in repro (currently $75) and the original 1970 Cuda cap installed. There is an incorrect repro out there but it has raised lettering with the ANTI SURGE on top and the VENTED on the bottom.

 

[Cuda U Code]

The 1970 VENTED ANTI SURGE fuel cap in repro (currently $75) and the original 1970 Cuda cap installed. There is an incorrect repro out there but it has raised lettering with the ANTI SURGE on top and the VENTED on the bottom.
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Thanks for this info.